Amitriptyline

Amitriptyline
Formula C20H23N
Molar Mass (g·mol−1) 277,4033
Melting Point (°C) 196-197
Boiling Point (°C) 410,26
PKS Value 9,4
CAS Number 50-48-6
PUB Number 2160
Drugbank ID DB00321
Solubility soluble in water

Basics

Amitriptyline belongs to the tricyclic antidepressants (chemical compounds with a tripartite ring system) and is used to treat depressive disorders as well as depression-associated anxiety. Because of its analgesic properties, the drug is also used to relieve neuropathic pain (nerve pain).
Off-Label wird es unter anderem beim Reizdarmsyndrom, Schlafstörungen bzw. Schlaflosigkeit und weiteren chronischen Schmerzerkrankungen verabreicht.

Until the introduction of serotonin reuptake inhibitors, amitriptyline was the most commonly prescribed antidepressant.

Pharmacology

Pharmacodynamics

Amitriptyline has antidepressant, analgesic, antianxiety, and sedative effects. The reduction of depressive symptoms is explained by the fact that a deficiency of neurotransmitters in the brain leads to depressive effects, and amitriptyline counteracts this mechanism. In the central nervous system, the active ingredient inhibits the reuptake of neurotransmitters (primarily serotonin and norepinephrine) into the presynaptic cell, i.e., in front of the synapse, which increases the concentration of mood-regulating neurotransmitters between the nerve cells. In addition, the sensitivity of the receptors is downregulated by the increased accumulation of neurotransmitters. Since this effect has a duration of about 2-3 weeks, the mood-enhancing effects are delayed.

The depressant and sleep-inducing effects of amitriptyline are due to inhibition of the neurotransmitter acetylcholine, and the analgesic effects occur due to increased serotonin concentrations.

Pharmacokinetics

The drug is rapidly absorbed after oral administration, with a bioavailability of only 30-60%. In the blood, the maximum concentration is reached 2-12 hours after oral or intramuscular administration and circulates there as well as in the tissues bound to 95% protein. Due to its fat-soluble properties, amitriptyline is distributed throughout the organism. Due to the cleavage of the methyl group and the introduction of hydroxyl groups (hydroxylation) into the molecule, amitriptyline is metabolized in the liver. As a result of genetically determined differences in hydroxylation function, 3-5% of the population have elevated plasma concentrations. The half-life is approximately 25 hours, although this is prolonged in the elderly.
Das Arzneimittel und seine Zwischenprodukte werden hauptsächlich im Urin ausgeschieden.

Contraindications

Amitriptyline should not be taken in case of hypersensitivity, intoxication, urinary retention or narrowing in the gastric outlet or intestinal obstruction due to intestinal paralysis.

Unless urgently needed, pregnant women should not take the antidepressant and breastfeeding women should either stop taking it or stop breastfeeding.

Drug Interactions

There should be an interval of at least 14 days between the use of tricyclic antidepressants and MAO inhibitors (e.g. tranylcypromine, selegilline, rasagilline, moclobemide) to avoid possible interactions.
Amitriptylin kann die Wirkung von Medikamenten zur Behandlung von Bluthochdruck (Guanethidin, Clonidin) mindern.
Weiters beeinflusst Amitriptylin möglicherweise die Wirkung von Cumarinen (z.B. Phenprocoumon), weshalb bei gleichzeitiger Anwendung die Blutparameter regelmäßig kontrolliert werden sollten.

An increase in effect occurs with drugs such as fluoxetine, fluvoxamine, cimetidine, and neuroleptics, and a decrease in effect occurs with concomitant use of St. John's wort.

Toxicity

Side effects

The most common typical side effects include:

  • Dry mouth
  • Visual disturbances
  • headache, dizziness
  • constipation and nausea
  • Drowsiness
  • low blood pressure
  • Weight gain
  • profuse sweating and tremor

Psychological side effects include fatigue and confusion.

Toxicological data

The effects of overdose are exacerbated with concomitant use of alcohol and other psychotropic drugs.
Die geringste bekannte toxische Dosis beträgt oral bei Kindern 4167 μg/kg, bei Frauen 10 mg/kg, und intermittierend bei Männern 714 μg/kg/Tag.

Markus Falkenstätter

Markus Falkenstätter
Author

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer
Lector

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

Your personal medicine assistent

afgis-Qualitätslogo mit Ablauf Jahr/Monat: Mit einem Klick auf das Logo öffnet sich ein neues Bildschirmfenster mit Informationen über Medikamio GmbH & Co KG und sein/ihr Internet-Angebot: medikamio.com/ This website is certified by Health On the Net Foundation. Click to verify.
Drugs

Search our database for drugs, sorted from A-Z with their effects and ingredients.

Substances

All substances with their common uses, chemical components and medical products which contain them.

Diseases

Causes, symptoms and treatment for the most common diseases and injuries.

The contents shown do not replace the original package insert of the medicinal product, especially with regard to dosage and effect of the individual products. We cannot assume any liability for the correctness of the data, as the data was partly converted automatically. A doctor should always be consulted for diagnoses and other health questions. Further information on this topic can be found here.